Horn type detonation attenuation means for internal combustion engines



Aug. 28, 1956 A. G. BODINE, JR 2,760,476

HORN TYPE DETONATION ATTENUATION MEANS FOR INTERNAL COMBUSTION ENGINES Ongmal Flled July 2 1951 INVENTOR. A4 55A? 7 6.130120%, Jk.

United States Patent HORN TYPE DETONATION A'ITENUATION MEANS FOR INTERVAL COMBUSTION ENGINES Albert G. Bodine, In, Van Nuys, Calif.

Original application July 2, 1951, Serial No. 234,688, now

Patent N 2,573,536, dated October 30, 1951. Divided and application October 24, 1951, Serial No. 252,818, new Patent No. 2,738,781, dated March 20, 1956. Divided and application December 6, 1955, Serial No. 551,263. Again divided and this application April 16, 1956, Serial No. 578,473

2 Claims. (Cl. 123191) This invention relates generally to internal combustion engines and to means for suppressing irregular burning and detonation of fuel-air mixture therein. The invention is based on my discovery that detonation in combustion engines involves acoustic phenomena and can be alleviated by means of certain acoustic apparatus used in combination with the combustion chamber.

The present application is a division of my copending application Ser. No. 551,263, filed December 6, 1955, allowed February 15, 1956, entitled Piston Carried Detonation Suppression Means for Internal Combustion Engines. That parent application was in turn a division of my application Ser. No. 252,818, filed October 24, 1951, entitled Engine Detonation Control by Acoustic Methods and Apparatus, now Patent No. 2,738,781, which application was a division of my earlier application Ser. No. 234,688, filed July 2, 1951, entitled Engine Detonation Control by Acoustic Methods and Apparatus, now Patent No. 2,573,536.

The present invention is based on the fact that detonation in an engine combustion chamber produces sound Waves, a large part of which rise to high amplitude at resonant frequencies of the chamber, and on my discovery that the sound waves produce the various wellknown and harmful manifestations of detonation. According to my basic invention, I inhibit or attenuate these harmful effects by interfering with or attenuating the high amplitude detonation-induced sound waves, and this is done by use in connection with the combustion chamber of acoustic attenuation means made responsive to the frequencies at which the detonation induced sound waves build up to high amplitudes.

My aforementioned Patent No. 2,573,536 taught the use of horn-type attenuators coupled to the combustion chambers of internal combustion engines for purpose of detonation suppression. An object of the present invention is the provision of a practical and efiective form of horn type attenuator capable of ready incorporation within the piston of the engine.

The invention will be best understood from the following detailed description of an illustrative embodiment thereof, reference for this purpose being had to the accompanying drawings, in which:

Fig. 1 is a vertical medial section through an internal combustion engine incorporating within the piston thereof the attenuation means of the invention, the piston being shown in elevation; and

Fig. 2 is a vertical medial section through the piston head 11, piston 14 working in cylinder 15 in head 10,

exhaust valve 16 and spark plug 17. An intake valve, not shown, will be understood to be located along-side exhaust valve 16, out of the plane of the paper. Head 11 has an inner combustion chamber wall 20, enclosing a combustion chamber space 21 over the cylinder and valve, as shown.

Piston 14 has a plurality of substantially vertical bores 25 extending downwardly through a piston body structure 26 from the upper end of the piston, and received in each such bore is a cylindrical plug 27 formed with a horn-shaped passage 28.' Bore 25 is enlarged near its upper end, as at 25a, to receive an enlarged head end portion 29 of plug 27, and the plug, after installation is secured in position as by peening at 30.

The throat of the horn opens through the inner or lower end of plug 27, as indicated at 32, to groove 33 which communicates with a spiral groove 34 formed around the plug 27. The groove 33 and spiral groove 34 form a long attenuation passage of relatively small cross section communicating with the throat of the horn.

The horn passage 28 may be made substantially exponential in taper. The theory of attenuation of detonation sound waves by means of exponential horns terminated by an attenuation means, such as a long, fine groove or passageway, is set forth in full in my aforementioned Patent No. 2,573,536, and need not be repeated herein. It is of course necessary, as always, to have the taper and other significant dimensions of the horn such as will receive those detonation wave frequencies which are to be attenuated. This art is well understood, and is referred to at length in the aforementioned issued patent.

The advantages of the present invention are the effectiveness of the type of attenuator provided, andthe ease by which such an attenuator may be incorporated in the piston of a conventional engine. It will further be noted that the attenuator of the invention may be readily removed as a whole from the piston at any time that the head of the engine is removed, for purpose of servicing. It will be understood that the drawings and description are merely illustrative of one specific embodiment of the invention, and that various changes in design, structure and arrangement may be made Without departing from the spirit and scope of the appended claims.

.I claim:

1. For use with an internal combustion engine having a combustion chamber and a cylinder opening into said chamber, a piston adapted for reciprocation in said cylinder, said piston having a top and side Wall structure, there being a bore extending downwardly into said top and side wall structure, a cylindrical plug in said bore having a horn passage therethrough whose mouth opens through the top of the piston and whose throat is at the lower end of said plug, and sound wave attenuation means communicating with said throat. 2. The subject matter of claim 1, in which said attenuation means comprises a groove formed between said plug and bore.

No references cited. 

